As data storage densities in magnetic recording continue to progress in an effort to increase the storage capacity of hard disc drives, magnetic transition (bit) dimensions and recording head critical features are being pushed below 100 nm. In addition, making the recording medium stable at higher areal densities requires magnetically harder (high coercivity) storage medium materials. Traditionally, writing to a harder medium has been achieved by increasing the saturation magnetization, or 4πMs value, of the magnetic material of the inductive write head, thus bolstering the magnetic field applied to the medium. Though there has been some success in materials research efforts to increase Ms of the write head, the rate of increase is not sufficient to sustain the annual growth rate of bit areal densities in disc storage. Another way to write to progressively harder medium is to locally reduce the coercivity of the medium during the writing process. Typically, this would be accomplished by locally heating the medium (by optical, or, more generally, electromagnetic stimulation) to lower its temperature-dependent coercivity during the writing process. This technique has thus far been limited to proof of concept laboratory demonstrations.
Accordingly, there is a need for a recording head that is capable of overcoming the high coercivity of magnetic storage media, and which would be practical to manufacture.